DE1964915A1 - Thermoplastic compositions based on polymers and copolymers of optionally substituted vinyl aromatic hydrocarbons - Google Patents

Description

PATENT LAWYERS DR.-ING. BY KREISLER DR.-ING. SCHÖNWALD DR.-ING. TH. MEYER DR. FUES DlPL.-CHEM. ALEK VON KREISLER DIPL.-CHEM. CAROLA KELLER DR.-ING. KLDPSCH COLOGNE 1, DEICHMANNHAUS

Cologne, December 23rd, 1969 Ke / Ax

UGINE KUHLMANN,

10, Rue du General Foy Paris VIII (France).

Thermoplastic compositions based on polymers and copolymers of optionally substituted vinyl aromatic Hydrocarbons

The invention relates to thermoplastic compositions based on styrene polymers with improved processing properties, in particular thermoplastic compositions based on styrene polymers, which are easier to process in plastic and have an elastoplastic state and, in particular after admixing a blowing agent, result in foamable masses, the improved properties compared to usual \ Chen have masses based on styrene polymers.

The term "styrenic polymers" as used herein includes homopolymers of unsubstituted and substituted vinyl aromatics Hydrocarbon monomers and copolymers of these monomers with themselves and / or with other copolymerizable Monomers of the type mentioned below.

A wide variety of processes are used to produce thermoplastic materials based on styrene polymers Manufacture finished products or objects with a wide variety of shapes, dimensions and properties. To this Methods include, for example, calendering, pressing; Injection molding, extrusion and thermoforming.

QQ98S2 / 2067

ORIGINAL INSPECTED

The same procedures are applicable for foamable Masses made by adding a blowing agent to styrene polymers are obtained, and from which foamed products or articles are obtained by heating, their Volume weight due to the presence of a large number of gas-filled cavities distributed throughout the mass is decreased.

^. _m and 1 5 ^ 5 573

The French patent specification 1 498 620 / and the French Additional patent specifications 94 122 and 14-5 290 describe a process for the extrusion of elongated products that have a certain, constant cross-section, an inner cell structure and a non-foamed outer skin exhibit. Another known method is the production of a foamed article from a preliminary product possible, which contains a blowing agent with which the ■ foaming is possible at the desired moment. For example Such an article, which contains a blowing agent, can be molded and then foamed by placing it on a temperature is heated that is above the decomposition or volatilization temperature of the propellant. In this way, a calendered sheet product that contains such a blowing agent, produced and foamed by thermoforming.

'It has now been found that the preparability of thermoplastic styrene polymers, particularly with regard to stretching or elongation in processing methods such as the thermal deformation for the production of foils, in which a surface enlargement occurs, and with regard to the Surprisingly, foamability in the various foaming processes is significantly increased when a resinous styrene polymer is admixed with the Base polymer is compatible and has a very high average molecular weight.

In processes that involve stretching or surface enlargement are connected by polystyrene foils,

009852/2067

result in mixtures containing such a high molecular weight styrene polymer added, films which in higher Dimensions can be stretched without tearing, and in any case the production of molded parts with better looks 5 "of the surface allow.

In the case of foam processes, it is due to the admixture of the additional polymer by any desired method, in particular by the processes mentioned above, molded parts with very low density and very fine and even cell structure and accordingly with a better surface quality and to produce improved mechanical properties, in particular with regard to impact strength.

It is believed that these results are attributed to the fact can be that in the case of foamable compositions that inhibit foaming

Phenomena with the viscoelastic state of the thermoplastic Base material at the temperature used and its rate of solidification during the Cooling related. This can be justified by the fact that it is necessary for the formation of pores, that the thermoplastic material must not be too viscous at the temperature used, so that the gas bubbles can be trained quickly. However, if the material has insufficient elasticity when hot, form there are gas bubbles, but it can be seen that the pores unite. The cell structure obtained is irregular, and the finished product has a poor surface and mechanical properties.

Furthermore, the cell structure can only be preserved if that JO material solidifies quickly on cooling. If this If this is not the case, the falling gas pressure causes the material to shrink, reducing its appearance the surface is impaired and the density increases will. This shrinkage is particularly evident in cases where the thermoplastic material is dispersed in

009852/2067

Form contains a plasticizer or an elastomer, which has been added to improve the impact strength are.

Similar conditions apply to the stretching of compact films. If there is insufficient elasticity of the material, not tearing of the foils results in at least one poor-looking surface being formed.

The invention relates to thermoplastic compositions based on styrene polymers with improved processing properties, especially with foam processes. These thermoplastic compositions contain a base polymer styrene thermoplastic polymer (A) which is a resinous thermoplastic polymer (B) is admixed, which by Polymerization of at least one styrene monomer or copolymerization at least one of these monomers with a comonomer which contains a radical of the formula CH2 = CC, has been obtained, has an average molecular weight of more than 500,000, preferably of more than 1,000,000, but in any case above that of the base polymer (A), and good compatibility with the thermoplastic Having styrene polymer (A).

If these compositions are to be used for the production of foamed products, they also contain a Propellant. They can also contain the usual additives necessary for their processing and for the intended use Intended use of the finished products are necessary, e.g. antioxidants, stabilizers, Lubricants, plasticizers, radiation protection agents, antistatic agents, fillers and reinforcing fillers and

JO coloring agents.

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The molecular weight of the thermoplastic polymers (a) and (B) is determined with the aid of the well-known Staudinger-Mark-Houwink equation fy] - KM ⁰⁰ , where M is the average molecular weight, {η] the intrinsic viscosity in a given solvent how butanone is and K and α are specific parameters of the polymer-solvent pair, which can generally be taken from tables, e.g. from the table in the book "Polymer Handbook" by Brandrupt and Immergut, edited by Interscience Publishers.

The "compatibility" that the two polymers (A) and (B) must have in order for the invention to work under good conditions Can be realized is a property that can never be scientifically achieved in a completely satisfactory manner although it is of considerable practical importance and known to any person skilled in the art. Without on very controversial details regarding the partial mutual miscibility of the polymers in question enter into, the view is taken here that two polymers are compatible, if possible, they to mix so that a material is obtained with a mechanical behavior that is as good or better

than that of the weaker of the two materials. According to this definition and as an example, a Styro1-Acry1-nitrile copolymer, that is 70 parts of styrene and 30 parts Contains acrylonitrile, compatible with an ABS terpolymer, the crosslinked dispersed by grafting 30 parts of styrene and 15 parts of acrylonitrile to 55 parts Polybutadiene is obtained in latex form, while a styrene homopolymer and the above-mentioned ABS terpolymer are incompatible are.

The proportion of the added polymer (B) in the mixture must depending on the base polymer, the processing method, the desired density of the foamed material and on the molecular weight of the polymer added. To a given degree of foaming to achieve, which is characterized, for example, by the volume weight, is the required proportion of the added The higher its molecular weight, the lower the polymer is.

In general, advantageous results are obtained when 0.2 to 80, preferably 1 to 40 parts by weight of the polymer (B), its molecular weight above $ 00,000, preferably over 1,000,000 is added per 100 parts of the base polymer (A).

Any blowing agent can be added to a foamable composition according to the invention. For example, are suitable Gases, aliphatic hydrocarbons such as pentane, hexane and heptane, chlorine or fluorine containing derivatives of aliphatic hydrocarbons, e.g. methylene chloride and chlorinated ethylene, or chemical blowing agents, which result in the formation of a gas when exposed to heat decompose, and chemical blowing agents such as azo compounds, hydrazides, amine dibrites, bicarbonates and oxalates. These Listing int not exhaustive. The choice of a fuel tank han ^ fc of the desired properties the ye-

009862/2067 ^ _{0 0 RIG!} “ _AL

foamed material, e.g. food purity and flame retardancy, as well as the process used and on the temperature. The blowing agent may be previously added to the base polymer or the additive polymer or any other Component of the mixture admixed or during the mixing of the various ingredients or at the time be added to the mixture after use.

Possible styrene base polymer (A) are: a) Homopoly mers of styrene or of ring-substituted or in oc-

10-position substituted styrene derivatives such as chlorine or Dichlorostyrene, vinyltoluene and α-methylstyrene or copoly mers of styrene with such styrene derivatives and copolymers of styrene and / or these styrene derivatives with a or more copolymerizable monomers such as acrylonitrile, methacrylonitrile, acrylic and methacrylic acid and their Alkyl esters including the methyl, ethyl and butyl esters, b) homopolymers or copolymers of the above Monomers with a small proportion of crosslinking polyfunctional comonomers, c) mixtures of polymers of the abovementioned types (a) and (b), d) mixtures of one or more polymers of the abovementioned types (a) and (b) with one or more elastomers that improve the impact strength, e.g. polystyrene, which with a GR-S rubber is reinforced, or a graft polymer of styrene on a polybutadiene elastomer, styrene-acrylonitrile copolymers with an in aqueous emulsion produced crosslinked acrylonitrile-butadiene elastomers are reinforced, or graft polymers of acrylonitrile and styrene on a polybutadiene elastomer (ABS) or on a polybutadiene or a saturated acrylic polymer or polyolefin or vinyl ethylene acetate elastomers.

The polymers (B) to be used in the thermoplastic compositions according to the invention are, as already mentioned, resinous polymers produced by polymerization at least

009852/2067

of a styrene monomer or by copolymerization of a such monomers with a comonomer which contains a radical of the formula CH ^ = CC can be obtained. As examples of these added polymers (B) may be mentioned:

by polymers produced by ionic polymerization or / free Radical initiated polymerization of vinyl aromatic hydrocarbon monomers (styrene and α-methylstyrene) obtained styrene-acrylonitrile copolymers, polymers of the same type in which the styrene partially and / or

Ί0 the acrylonitrile partially or completely by the corresponding substituted monomers have been replaced, e.g. styrene-methacrylonitrile copolymers or oo-methylstyrene-styrene-acrylonitrile terpolymers, Copolymers of styrene and / or α-methylstyrene with methacrylate and terpolymers of styrene, acrylonitrile and methyl methacrylate.

It can also be advantageous to add other comonomers which, for example, have a crosslinking effect, in small amounts of less than 10% by weight, based on the total monomers used. For example, acrylonitrile-styrene copolymers containing less than 0% divinylbenzene can be used for this purpose.

The above-mentioned additional polymers (B) can be prepared by any known polymerization method will. However, production by polymerization in an aqueous emulsion is preferred. In this procedure It is easier to manufacture high molecular weight products because the molecular weight is adjusted by choice the polymerization temperature, the amount of initiator and possibly the amount of chain transfer agent is.

In the case of polymerization in aqueous emulsion, it is also possible to produce polymers directly in powder form, for example by simply atomizing the latex. This powder form favors good distribution

^009852/2067 _BATH

of the additional polymer in the foamable base mixture. An advantageous method for admixing the additive ' polymer (B) to thermoplastic base mass (A) consists in the mixing of the powder in a high-speed Mixer. The propellants, e.g. nitrogen compounds, hydrazides, amine nitrites or simply bicarbonates or Oxalates and other additives, e.g. stabilizers, antioxidants, lubricants, plasticizers, antistatic agents, Nucleating agents, flame retardants, fillers, and dyes, can also be used in this high-speed mixers can be incorporated

When the thermoplastic base polymer (A) is prepared in emulsion, it may also be advantageous to mix it with the additive polymer in the form of a latex, whereby a very homogeneous mixing is achieved _t

Another method to achieve a homogeneous mixture on the basis of the thermoplastic material and the additional polymer consists in carrying out the polymerization one of the two components in the presence of the other.

Examples of particularly advantageous uses of the invention include: If the base polymer (A) is an optionally is styrene homopolymer reinforced with an elastomer, the additional polymer (B) is advantageous > 5 a styrene homopolymer or a styrene-methyl methacrylate copolymer 5 if the base polymer (A) is a styrene-acrylic

, t

nitrile copolymer or an ABS terpolymer A styrene-acrylonitrile copolymer is advantageously used as the additional polymer (B) used·

> 0 In other cases, especially in the increasingly common ones more complicated cases in which the base polymer (A) consists of a resinous polymer which has number, rich monomers, ζ »8 · styrene or α-methylstyrene, acrylonitrile or methacrylonitrile, methyl methacrylate and the like.

contains in different proportions, and that can be further reinforced with a grafted or ungrafted elastomer leaves one with a choice of the additional polymer (B) by its probable compatibility with the resinous polymer (A) and of guide economic considerations.

In the following examples, the parts are parts by weight, unless otherwise stated.

example 1

Production of very high molecular weight polystyrenes (hereinafter referred to as PS)

An emulsion of the following composition was placed in a reactor:
Styrene. 100 parts

V / ater 180 parts

Sodium tetrapropylbenzenesulfonate 2 parts potassium persulfate 0.075 parts

Sodium bicarbonate 0.5 parts

The mixture was ^{stirred at 70 0} O for 2 hours and then at 8O ⁰ O for 30 minutes in order to complete the reaction. The Iiatex obtained was dried, 98 parts of polystyrene being obtained, which had an intrinsic viscosity (IV) of 4.2 dl / g, measured in butanone at 25 ° C (K - 19.5 x 10 ", α« 0.635 ) ι This corresponds to a molecular weight of about 7-10.

When 0.015 parts of tetrapropyl mercaptan are added to the starting mixture described above, the result is that Polystyrene has an intrinsic viscosity of 2.7 dl / g corresponding to a molecular weight; from 3,200,000,

009152/2067 ß ^AD original

Example 2

Preparation of very high molecular weight styrene-acrylonitrile copolymers (hereinafter referred to as "SIT") An emulsion of the following composition was placed in a reactor:

Styrene 72 parts

Acrylonitrile _ 28 "

Water 180 "

Sodium Tetrapropylbenzenesulfonate 2 "™

LO potassium persulfate 0.075 "

Sodium bicarbonate 0.5 "

In the manner described in Example 1, 98 parts of a copolymer were obtained which had an intrinsic viscosity (IV) of 10.3 dl / g, measured in butanone at 30 ^° G (K = 36 χ 10 "" - ⁷ ; α = 0.62). This corresponds to a molecular weight of about 14 χ 10.

If 0.025 part of tetrapropyl mercaptan is added to the starting mixture described above, the copolymer obtained has an intrinsic viscosity of 4 dl / g, corresponding to a molecular weight of about 3 10. (

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Example 3

Production of very high molecular weight styrene-methyl methacrylate copolymers (hereinafter referred to as S-MMA)

An emulsion of the following composition was placed in a reactor given:

Methyl methacrylate 56 parts

Styrene 44 parts

Water - I80 parts

Sodium tetrapropylbenzenesulfonate 2 parts

Potassium persulfate o, o75 parts

Sodium carbonate 0.5 parts

In the manner described in Example 1, 98 parts of a styrene-methyl methacrylate copolymer which had an intrinsic viscosity (IV) of 6.5 dl / g, measured in butanone at 25 ° C., were obtained.

If o, o25 parts of tetrapropyl mercaptan are added to the starting mixture of the above composition, has the formed styrene-methyl methacrylate copolymer an intrinsic viscosity of 3.1 dl / g.

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BATH ORIGINAL

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Example 4

Production of very high molecular weight styrene-acrylonitrile-methyl methacrylate copolymers (hereinafter referred to as SAN-MMA ) '

An emulsion of the following composition was placed in a reactor given:

Styrene 55 parts

Methyl methacrylate 45 parts

Acrylonitrile 45 parts

Water . 18o parts

Sodium tetrapropylbenzene

sulfonate * 2 parts

Potassium persulfate o, o75 parts

Sodium bicarbonate 0.5 parts

In the manner described in Example 1, parts of a styrene-acrylonitrile-methyl methacrylate copolymer were obtained which had an intrinsic viscosity (IV) of 8.9 dl / g, measured in butanone at 25 ^° C.

If 0.03 parts of tetrapropyl mercaptan are added to the starting mixture of the above composition, has formed .styrene-acrylonitrile-methyl methacrylate copolymers an intrinsic viscosity of 4.3 dl / g.

009862/2087

Examples 5 to Io Extrusion of molded parts from polystyrene foam

To produce a cylindrical rod with a diameter of J> 2 mm according to the process described in French Patent 1,498,620 and which enables the production of strands with a dense surface, various foamable compositions were extruded, the base polymer being a polystyrene with or without an additive of a very high molecular weight polystyrene prepared according to Example 1 with an intrinsic viscosity of 4.2 dl / g in butanone at 25 ° C. The basic mix of these extrusion compounds had the following composition:

Polystyrene as the base polymer} loo parts Added polystyrene J

Sodium bicarbonate 5 parts

Stearic acid o, l parts

Paraffin oil - o, o25 parts

These mixtures can be used in different proportions the polystyrene used as the base polymer and the very high molecular weight additional polymer. In a first series of experiments, the base polymer was a bead-shaped, foamable polystyrene of the trade name "LORKACHL C 12o" and in a second series of experiments a pearl-shaped, foamable polystyrene of high impact strength, the ^ under the designation "LORKACEL C 124" is on the market.

00SB52 / 20S7

-YES-

The extrusion machine consisted of the following parts: an AITI) O UART screw press with powder feed, which has a diameter of 40 mm, a length of 20 diameters, a screw of the type ANDOUART RB 50, one Hose injection mold with an inner diameter of 31 »8mm and an axial mandrel of 27 »2 mm in diameter, a calibration nozzle with a diameter of 32.3 mm and 210 mm Length that followed the injection mold and was cooled by constant circulation of water, a 2 m long water cooling bath and a pull-off device consisting of caterpillars with rubber soles

The extruder operated under the following conditions: The screw speed was 50 tJpHj ₀ the screw was cooled with water that was circulated at a constant Meago and an outlet temperature of ^ U ⁰ Q Siatts «. Along the cylinder, the following temperatures were from the rear up front; 110-155 ⁰ The head temperature was 130 ⁰ G ₅ the temperature of the nozzle 120 ° C.

In the experiments in which the Str-angpr-eBbedingungen were held constant, the massisale Äfezngsge ™ was chosen to speed the strand _s ümB a solid product was obtained. The corresponding specific Qe. weight was noted. The results obtained as a function of the type of polystyrene used as the base polymer and the quantitative ratio of the base polymer to the strongest polystyrene are nsönstelisad is. Table I named.

BUILDING

Table I. Example No. 5 6 7 8 9 Io

Pearl-shaped
• polystyrene
"LORKACEL C 12o",

Share loo 9o 8o

Pearl-shaped
Polystyrene
"LORKACEL C 124",
Parts - loo 9o 8o

Added

Polystyrene,

IV 4.2 dl / g,

Parts * 0 Io 2o O Io 2o

Maximum take-off speed
ability,
cm / minute J4 8o 9o 28 4o 5o

Specific
Weight of

Strands o, 55 o, 4o o, j55 0.63 0.50 o, 45

Spreading,

kg / hour 9 13 * 5 15.2 8.5 9.7 lo, 9

The addition of a very high molecular weight polystyrene to a polystyrene or a polystyrene of high

Impact strength therefore enables an improvement in. Foamability: strands with a lower density are obtained with increased hourly output.

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BATH

Examples 11 to 14

Extrusion of foamed molded parts made of polystyrene by extrusion _r

The mixtures mentioned in Examples 5 to Io which but instead of the added polystyrene contained the same amounts of the S-MMA prepared according to Example 3, were extruded under the same conditions and in the same test series as for the Examples 5 to Io described. The results are

hereinafter referred to in Table II in the Examples, etc. have been included for comparison purposes, 5 and 8. FIG.

, Table II

Example No. 5 H 12 8 13 14

Pearly
Polystyrene

"LORKACEL C 12o",

Share loo 9o 8o

Pearl-shaped
Polystyrene
"LORKACEL C 124",

Parts - loo 9o 8o

Added _Λ

S-MMA copolymer!

IV = 6.5 dl / g,
Parts 0 Io 2o 0 Io 2o

Maximum take-off speed,
cm / minute 34 6l '70 28 36 43

Density of the
Strand

(Specific gravity

of rod) o, 55 o, 39 o, 34 0.63 0.51 o, 46

Spreading,

9 11.5 12.7 8.5 9.3 lo, 2

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The admixture of a very high molecular weight styrene-methyl methacrylate copolymer to polystyrene or to impact-resistant polystyrene thus enables an improvement in the Foaming ability: Strands of lower density are obtained.

Examples 15-17

Production of foamed molded parts from A3S polymers by extrusion

Mixtures 9, Io and 11, which are an ABS polymer (acrylonitrile-butadiene-styrene terpolymer, trade name "LORKARIL JA") and, as an additional polymer, the SN resin produced according to Example 2 (IV = 4 dl / g in butanone at 50 ° C) were extruded with the same equipment that was used in the case of Examples 5 to 11, at the same temperatures:

Extrusion press barrel: llo-155-17o-17o ° C Head temperature: 13o ° C

Shower temperature: 12o ° C

The results obtained are shown in Table III below.

Table III

Example no. ' 15th 16 17th ABS powder ¹¹ LORKAIiIL JA ", parts 100 95 90 Additional polymer: powdery
NS resin, IV = 4 dl / g, parts 0 5 10 Sodium bicarbonate 3 3 3 Maximum take-off speed,
cm / minute 35 50 60 Specific weight of the
massive strand 0.65 0.55 0.48 Output, kg / hour 11th 13.3 13.9

Output, kg / h

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BATH

- 4Θ ¹ -

$ 1

Examples l8 to 21

Production of foamed products from ABS polymers by extrusion

Mixtures containing the ABS terpolymer used in Examples 17 to 19 and one of the two as an additional polymer SAN-MMA copolymers prepared according to Example 4 were used with the same extruder and under the same conditions as in Examples 5 to Io described, extruded. The results obtained are shown in Table IV below, in the Examples included for comparison purposes.

15th Tabel IV 2o 21 Example no. loo 18th 19th 9o 80 ABS powder
"LORKARIL YES",
Parts 0 9o 80 Added
SAN-MMA-Copoly-
meres, IV =
8.9 dl / g parts Io 2o Io 2o Added
SAN-MMA-Copoly-
meres, IV =
4.3 dl / g, parts 3 3 3 Sodium bi carbonafc 35 3 3 49 * '62 Maximum deduction
speed,
cm / minute 0.65 55 7o 0 ^ 56 o, 45 Density of the
Strand 11th o, 5o o, 39 IS ₅ 4 «E- -J SV * Spreading,
kg / h 13th 14.5

0098S2 / 206 /

OBtGiNAL

The admixture of a very high molecular weight styrene-acrylonitrile ~ methyl methacrylate copolymer to an A3S terpolymer thus enables the foaming ability to be improved. It can be seen that for achieving

a given degree of foaming the required Proportion of added styrene-acrylonitrile-methyl methacrylate copolymer is so lower, the higher the molecular weight of this copolymer !! is.

Examples 22 to 37

Manufacture of foamed products by extrusion

with unhindered foaming at the nozzle outlet -

An ANLCUART extrusion press with a diameter of 40 mm .. and a length of 20 diameters and with a screw with a compression ratio of 2.5 was provided was used. The injection mold had a round nozzle outlet with a diameter of 9 mm. Dns from the Product emerging from the nozzle was picked up on a conveyor belt without cooling other than the ambient air.

The following extrusion conditions were kept constant for the various foamable mixtures described below:
Temperatures in the cylinder from back to front:

-110-14-0-160-170 ⁰ C Head temperature:. _ 140 ⁰ O
^ ₅ Büsenteaipsrstur: = 120 ⁰ C
SohneefeiKle speedi 20

ÖAD ORIGINAL

Sf) -

The material began to foam at the nozzle outlet. Of the The strand was deposited on the conveyor belt without any take-off, on which its diameter continued to increase. At a distance of ' 70 cm in front of the nozzle outlet, where the surface of the strand was sufficiently cooled and the product had assumed its final shape, samples were taken, their density and cross-section were determined. The cross-section was compared with the cross-section of the nozzle to determine the Extent of foaming or the foaming rate j

.0 determine the speed z-u.

The following in Table V; called foaming abilities

All-purpose mixtures based on / polystyrene and impact-resistant polystyrene, the 5 parts of sodium bicarbonate as a blowing agent were in the device described above under the above-mentioned working conditions

extruded. The polymer added was a polystyrene produced according to Example 1 with an Intrinsic Viscosity of 4.2 dl / g.

Table V
> 0 -examples no . 22 23 24 25

Polystyrene (LOBKAGEL (

G 120), parts 100 80

gz?% es polystyrene
(LORKACEL, 0 124), parts - - 100 80

Added polystyrene, IV = 4.2 dl / g, parts density
Degree of foaming

0 30th 20th 0 36 20th , 22 O, 0.15 O, 0 12th 24 8th 15th

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BATH ORIGINAL

196491α

U.

Mixtures based on polystyrene having the same composition had, in which, however, the additional polystyrene by a obtained according to Example 3 styrene-methyl methacrylate copolymer (S-MMA) were extruded with the extruder described above under the same conditions. The received Results are reported in Table VI below, which includes Examples 22 and 24 for comparative purposes became.

. · Table VI

Example No. 22? 2 6 24 2 7

Pearl-shaped
Polystyrene
"LORKACEL C 12o",
Share loo 8o

Pearl-shaped
Polystyrene
"LORKACEL.C 124",
• Parts 0 2o loo 80 20th Added
S-MMA copolymer,
IV = 3.1 dl / g,
Parts o, 3o
12th o, 16
23 0 2o 25th Volume weight
Foaming speed
speed o, 36
8th o, 20
l6

Using the same device and under the same conditions as the mixtures are extruded, the base polymer is a styrene-acrylonitrile copolymer (Trade name DIKARYL) or an A3S elastomer and a styrene-acrylonitrile copolymer as an additional polymer which had been prepared according to Example 2 contained. The results are in the table below VII called.

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BATH ORIGINAL

- ββ -

Table VII
Example Mr. 28 29 50 51 52 55

Styrene-acrylonitrile copolymer
'5 (DIKAHYL), parts 100 90 80

ABS Terr> o lymeres

(LOIOCAHIL JA), parts - 100 90 80

Additional polymer SAN

I.V. 10.3 dl / g, parts 10 20 10 20 sodium bicarbonate,

Parts' 555555

Volume weight 0.52 0.25 0.10 0.60 0.55 0.21 Degree of foaming 5 21 26 M- 17 25 Two further series of tests were carried out using mixtures containing the ABS terpolymer "LOICARIL JA" or the Sjjyrol-Äcrylnitril copolymers ⁵¹ DIMRYL "as Grundpolyineres and the SAN-MMA copolymers prepared according to example 4 as an addition polymer containing" the results obtained are given below in Table VIII · Called, in the examples have been 28 and 31 included for comparison "purposes .

Table VIII

example Vr . 28 3h 55 31 36 57

Styrene-acrylonitrile-copoly-

more "DIMRYL",

Share loo 9o 80

A3S Terpol3nTieres
"LORKARIL YES",
Parts - loo 9c 3o

Added

SAN polymer

I.Vc = 10.5 dl / g.

Share Iq So ■ = · Ie : '; -_ ■

Hatriura bicarbonates

Parts 5 3 5 5

} \ auHicQ --rieht o _P 32 c.Sb O ₅ 13 o ₅ 6o

■ ν.: '. ·: Eifc g If; 25 h ία

ÖAD ORiQlMAu

These foaming tests clearly show that the addition of a very high molecular weight polymer of the type described above enables the formation of a uniform cell structure without cracks or unifying pores, the cell structure solidifies faster, so that the foam does not shrink and the product shortly after it emerges from the Nozzle assumes its final external shape.

Examples 38 to 43 Injection molding of blends based on polystyrene and

impact resistant polystyrene

Shoe heels with a volume of 98 cnr were made by injection molding with a SMAL press, which had a capacity of 135 g and provided with a screw with a compression ratio of 2.5 v / ar. The benefit of using the additive polymer was illustrated by two sets of injection molding trials: a) The amount of foamable material placed in the mold was varied so that maximum lightness was obtained. The following injection molding conditions wurcL ^s held constant:

Temperature at the inlet of the press: 120 ⁰ C temperature at the center of the press: 170 ⁰ C temperature of the nozzle: 190 ° C

Duration of the pressing process: 250 seconds

(230 seconds for the mold to cool, 10 seconds Injection process and 10 seconds demoulding).

b) The specific weight of the injection-molded heel was determined and the minimum duration the cooling of the mold, after which the article retained its shape after demolding. The others Injection molding conditions were maintained at the above values.

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BATH ORIGINAL

Commercial name foamable all-purpose polystyrene "LORKACEL 11" and high-impact, foamable polystyrene with the trade name "LORKACEL C 115" were used in various experiments with or without an additional polymer used, namely with a PS polymer prepared according to Example 1 or one prepared according to Example 3 S-MMA copolymers. In each pail there were three parts Sodium bicarbonate used as a propellant. The results of these experiments are given in Table IX below. "

Table IX Example No. 38 39 ^ o »1 ^ 2 43

Foamable
Polystyrene
"LORKACEL 11",

Parts * loo 85 85 - -

High impact,
'foamable

Polystyrene
"LORKACEL C 115",

Parts - loo 85 85

Added

PS polymer, I.V.

= 2.7 dl / g, parts 15 15 -

Added

S-MMA copolymer,

I.V. »3.1 dl / g,

Parts - - 15 - 15

achieved, small- '

ßtes density o, H5 0.36 0.33 o, 55 o, 45 0.39

Minimum cooling time
for a density of 0.45 »
Seconds 180 15o 17o 21o I80 2oo

_eAD

Examples 44 Mg 48 . . -

Injection molding of mixtures based on ABS terpolymers with foaming ____ »_____« __ »_______._ —— _

Using the same apparatus and under UEN same conditions as in Examples 38 to 4JJ the same tests were carried out with foamable mixtures for which the ABS · » Terpolymers "LORKARYL JA" and as an additional polymer das SAN copolymers prepared according to Example 2 or the SAN-MMA copolymers prepared according to Example 4 contained. The mixtures used and those obtained Results are reported in Table X below.

Table X Example no.44 45 46 47 48

ABS terpolymer "LORKARIL YES", Parts loo 9o · 85 9o 85

SAN copolymers, I.V. = 4 dl / g, Parts - Io 15 -

SAN-MMA copolymer,

I.V. - 4.3 dl / g,

Parts - - - Io 15

Sodium bicarbonate, Parts 5 5 5 5 5

Achieved, smallest density 0.60 o, 55 Q, 52 o, 5o o, 46

Minimum cooling time

for a space

weight of 0.00,

Seconds 22o 2oo 19o 21o 2oo

Examples 44 to 48 show that, as in the case of Extrusion by admixing an additional polymer according to the invention to form a foamable mixture for Injection molding is possible to obtain injection molded parts with a lower density. Furthermore, the same

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Volume weight, the time required to cool the mold before demoulding can be shortened, so that the production speed can be increased.

Another advantage that results from the admixture of the additional polymer of very high molecular weight of the invention, is the improvement of the surface quality of the injection molding of these products (( mix manufactured foamed moldings. The surface of the molded parts is smoother, much less porous and therefore less permeable. This is very important to the molded parts made by injection molding final lacquer or paint coatings are to be applied. The following example illustrates this

15. Advantage.

Example 49

Rectangular panels of 170 70 χ 10 mm were made through Injection molding with an ARBURG ALLROUNDER 300 injection - Casting machine made. In a first series of tests, the injection molding compound consisted of high impact strength foamable polystyrene "LORKACEL C 115" alone and in a second series of experiments from the same polystyrene, the 10 parts by weight of a high molecular weight polystyrene had been admixed with an intrinsic viscosity of 2.7 dl / g. The injection molding conditions were chosen so that plates with a density of 0.6 were obtained.

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When using the above-mentioned second mixture. the plates were decidedly smoother than the plates with pure polystyrene "LORKACEL C 115".

In order to evaluate this improvement, an apparatus which consisted of a cathode ray oscilloscope receiving signals .from a piezoelectric pickup head received, which was provided with a diamond needle.

This head rested on the surface with a pressure of Io g of the plate to be examined, while this is carried out with a slide at a speed of 2 cm / Selc. was moved. The vibrations displayed by the CRO and caused by the micro-roughness on the surface of the Plate generated are recorded with a POLAROID C 12 Tectronix camera.

The recordings obtained during this scanning of the two types of plates produced in the described manner show that the average amplitude of the vibrations ^{corresponding to the plates produced with the polymer 11} LORKACSL C 115 "alone is twice as large as the average amplitude of the plates made with the mixture of 90 parts of the polystyrene "LOR] CACEL C 115" and 10 parts of the high molecular weight polystyrene.

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BAD OftlÖJMÄL

Claims (1)

Claims 1.) Thermoplastic, after adding a propellant foamable compositions based on polymers and copolymers of optionally substituted vinylaromatic Hydrocarbons (styrene polymers) with improved processing properties, characterized by that they contain, as the base polymer, a thermoplastic styrene polymer (A), which is a resinous one thermoplastic polymer (B) is admixed, which by polymerization · at least one styrene monomer ™ or copolymerization of at least one of these monomers with a comonomer which is a radical of the formula CHp = C = contains, an average molecular weight of more than 500,000, preferably of more than 1,000,000, but which is in any case higher than that of the base polymer (A), and good compatibility with the thermoplastic styrene polymer (A). 2.) Thermoplastic compositions according to claim 1, characterized in that that they also contain a propellant and, if necessary, antioxidants, stabilizers, lubricants, ( Contain plasticizers, radiation protection agents, antistatic agents, fillers and / or coloring agents. j5.) Thermoplastic compositions according to claim 1 or 2, characterized characterized in that they are 0.2 to 80 parts by weight, preferably 1 to 4o parts by weight of the polymer (B) per Contain 100 parts by weight of the base polymer (A). k ») Thermoplastic compositions according to claims 1 to 3 *, characterized in that they contain as thermoplastic polymer (B) a polymer which has been produced by polymerization in an aqueous emulsion. 000852/2067, 5.) Thermoplastic compositions according to claim 1 to 4, characterized in that they are optionally used as the base polymer (A) styrene homopolymer reinforced with an elastomer and a styrene homopolymer as additional polymer (B) or a styrene-methyl methacrylate copolymer. 6.) Thermoplastic compositions according to claim 1 to 4, characterized in that they are a styrene as the base polymer (A) Acrylonitrile copolymer or an ABS terpolymer and, as an additional polymer (B), a styrene-acrylonitrile copolymer contain. 009852/2067